The value at 08340024 is the MCFBAH address. In this case, it is 00000027. The value at 08340020 is the MCFBAL address. In this case, it is e0000000. So you can build the MCFBA base address as: 0x27e0000000.
Run the following command to start the MC if it is not booted already.
Dump the log buffer structure at offset 0x01000000 into the MC firmware base 0x27e1000000 (as per the example).